Work vehicles, such as a motor grader or forestry machines, often operate in difficult terrain. A tandem axle can be incorporated into the motor grader to provide the transmission of power to front and rear wheels on one side of the axle. Tandem axles can include gear drives or chain drives to transfer power to the wheels mounted to the axle. When a work vehicle is driving over a tree stump or debris, for example, there may be a need for one wheel to be driven faster to move the vehicle along. In conventional tandem axle systems, however, a mechanical connection (e.g., dual sprockets or gears) between wheel ends is such that the main axle turns at a defined speed that is the same for both the front and rear axles.
As a result, there can be a substantial reduction in power consumption in many conventional tandem axle designs if the different wheels in a bogey assembly are not constrained to the other wheels. Moreover, some tandem axle designs may require different diameter wheels to be mounted at the front end and rear end of the axle. In this instance, however, the difference in wheel diameters can cause the wheels to fight one another when the vehicle is driving over rough terrain. This is again due to the mechanical connection between the main axle and the front and rear axles of the tandem axle. In other words, an external component may prevent the front and rear axles from operating at the same speed which results in inefficiencies and power losses in the bogey assembly. To resolve or overcome this power reduction, other conventional drive systems may include individual wheel motors mounted at each wheel to correct or compensate for wheel speed differences. This, however, can significantly increase the cost of the machine design without providing for optimal vehicle performance.